Broaching machine



July 12, 1949. o. w. BONNAFE BROACHING MACHINE z Sheets-Sheet 1 Filed Feb. 11, 1946 n w-l h l u o llll ATTY o. w. BONNAFE 2,475,690

BROACI IING MACHINE July 12,. 1949.

Filed Feb. 11, 1946 3 Sheefs$heet 2 July 12, 1949. w, BQNNAFE 2,475,690

\ BROACHING MACHINE Filed Feb. 11, 1946' 3 Sheets-Sheet 6 V EN TOR.

ATTY.

Patented July 12, 1949 "BRQA'CHING MACHINE :2 iOliver: -W-;' Bonnafe; Hudson,;Mass.,:='assignor. to aThmLanoime Machine. {Tool Company; Hudson, -;Mass.., acorporation of Maine Application February ,11, 1946,. Serial No; $646,907

This inventionrelatesto a bro-aching machine capable of general application but particularly designed ier broaching involuteteeth on-circular gear blanks.

It the general object of-myinventionto provide a-broachingfmachine 'by which involute spur gears may be 'accurately and automatically produced in reduced- "timeand at substantially less expense than "has heretofor prevailed.

To the attainment ofthis general object, I provide a machine inwhich a-sectional broach is given =a-continuous straight-line vertical travel axially of the gear blanksy and in which the gear bl'anks-=roll in a horizontal plane transversely across the cutting face ofthe continuously mov-v ing sectional :broach.

l 'also'prov-ide meansto positively advance each broach section through the cutting locus, means topositively'advance -each gear blank through the cutting locus; and -means to-positively rotate the gear bl'ankat a speed accurately corresponding tofits rolling-pitch line.

ytinvention turthercrelates to arrangements an combinations of parts whichfiwillbe hereinaftendesoribedand. more particu1arly pointed out imtheappendedmlaims.

preferred formwof the invention is. shown in the drawings, which "Fig. :1 is a partialisidaelevation of z-my improved breaching" :machiney zwith :parts of [the .casing showntindicated'. diagrammatically only;

Fig. :2 is a sectional plan-view; taken substantiallgalongwthalineiL-J inizFig. '1;

Fig. 3 is an enlarged sectional sidezelevationof certalnwork supportin and work-feeding structure;

Fig. 4 is a rear elevation of a portion of the sectionalrbmach'; i

Fig. 5 is a front elevation oiqonevbroachsection;

Fig. 6 is a side "elevatiom looking'in the direction oilthe arrow 6 in Fig. 5

title. 3 :Pisan. enlar ed .zpant al aplan view of 11 hmaz h section and. associated zeui am pa ly imiection;

18 .is matpartiaiside elevation of a -.":m'0:dified broach section guide; and

Fig. 9 is a partial front elevation of certain work table adjusting mechanism, looking in the direction of the arrow 9 in Fi 2.

Referring to the drawings, my improved broaching machine may be described as comprising broadly a broach-supporting and driving mechanism A and a Work-supporting and driving mechanism B.

The mehanism Acomprises a casing I 0 i havin gbearings for an :UDDEYCI'OSS shaft Hand a 1ower--cross shaift= Hy-each having apair of sprockets orguide discs 14 on which a sectional broach is-supported.--The shafts ll -an'd 12 are f-relywotatable and: the sprockets 14 have no driving funotion.

The sectional 'broach momprises broach sections shown in -detai-1*inFigs. =4, 5 'and G and each comprising a front plate 20 having parallel vertical rows 21 of broachingteeth 0n= its front face. Each front-platen ismounted on a back plate 22- having dipper ears 23 and lower ears 2'4, pivotallyconnected by c-ross rods 25- which maybe held from endwisedisplacement by screws 25. Theends oi?- the -rods"25 are received in'suitably spaced-notches in theperiphery of the guiding sprockets or discs l l:(Fig. 1)

Ihe-widtl'iof the front plate Zllis such that the number or rows 2 1 =of breaching teeth exceeds the number di -teeth in the gear to be-broached, so that the-gear blank will :perform slightly more than a complete revolution in rolling across the cutting face ob t-he -sectional-broachp 1 The ends ofthe-plateZfl-are groovedor recessed as shown in==Fig. Fraud-have a close sliding fit on fixed vertically extending guideways 2'9.

Each-preach --section-is provided on its 'rear fac with rack-plates 30-and3l (Fig. -4) =having helical 'rack teethdisposed at reversed angles to neutralize endthrust. Theserack teeth are ena ed by helical gears til'and 34' (Fig. 2) mounted ona "shaft 1-35 -rotata-ble in-fixed-bearings 36 and 3 l--and-provided with a-worm gear 38." The gear 38 is driven "by a-wormlfl =(Fig; 1) mounted on a shaft 'Mwhich is *driven from a motor M through a-pluralityof belts 42;- or-whichmay be continuously rotated "from any other convenient source of power.

With the driving-mechanism above described, it will be seen ,that the helical gears 33' and 3 are -continuo usly and--positively-rotatedand that they-engage the rack plates 30-and- 31" on the breaching sections as each-section passes through the broaching locusand that theypositively ad- Vance each jbroach "section as it performs its broaching operation. There is thus 'a direct application of power at the cutting point, and all lost motion, irregularity or chatter is effectively avoided.

As previously stated, the guiding sprockets or discs I4 have no drivin function and these discs may be replaced by fixed circular guideways 44 as shown in Fig. 8. v

The mechanism B for supporting and driving the gear blanks or other pieces of work comprises a pair of sprockets 60 (Figs. 2 and 3) loosely mounted on pivot studs 6| fixed in the frame 62 of the work table 63. Studs 64 in work-supporting blocks 65 are received in the notches of the sprockets 60, and adjacent blocks 65 are connected by links 66 as best shown in Fig. 2.

A gear 61 (Fig. 3) on a stud 68 is rotatably mounted in each block 65, and these gears 61 continuously engage a rack plate 69 which extends entirely around the work table 63 and which is semi-circular in its end portions and straight along its side portions. Each gear 61 and stud 68 is connected by gears 19 and H to rotate a stud 12, also mounted in the block 65.

Each stud 12 has provision for receiving a gear blank K and preventing relative rotation thereof on the stud. The gears and H are preferably of equal size, and the pitch line of the gear 61 is preferably of the same diameter as the pitchline of the gear to be cut from the blank K.

Each work-supporting block 65 has a segmental nut 14 which engages a lead screw 15 mounted on a shaft 16 extending parallel to the front face of the operatively-positioned broach section. The shaft 16 may be driven through gears 11 and 78 (Fig. 1) from a shaft 19 connected by belts 89 to a shaft 81 which is continuously rotated by a. suitable motor or other source of power, not shown.

All of the work-supporting parts thus far described are mounted on the work table 63 (Fig. 3), which is supported in suitable guideways 90 (Fig. 9) on a base 9| and which has a half nut 92 (Fig. 3) engaging an adjusting screw 93. The screw 93 is formed on a shaft 94 mounted in bearings on the base 9| and rotatable by a hand wheel 95 through reduction gears 96 and 91. By turning the hand wheel 95, the work table 63 and gear blanks K may be adjusted forward or rearward relative to the sectional broach to bring the pitch-line of the gear to be produced into alignment with the pitch-line of the broach.

The entire system of work-supporting blocks 65 is continuously advanced by engagement of the lead screw 15 with one or more of the segmental nuts I4 on the blocks 65 which are moving through the broaching locus. As each block is thus positively advanced, the gear 61 in said block is positively rotated by its engagement with the fixed rack plate 69. The diameter of the gear 67 is so related to the diameter of the gear blank K that the pitch-line of the gear blank will roll past the sectional broach at the same speed that the gear 61 rolls past the fixed rack plate 69. The gear blank K is thus positively rotated and at the same time is positively advanced past the sectional broach, and the sectional broach is continuously moved downward, thereby correctly developing and cutting involute teeth on the gear blank.

As has been previously stated, the width of the cutting face of each broach section is somewhat greater than the circumference of the gear blank, so that the blank will make something more than a complete revolution in passing across the cutting locus of the sectional broach. Thus a com- 4 plete gear will be produced by a single passage of the blank across the sectional broach,

Although the chain of work-supporting blocks moves continuously, the movement is not so rapid as to prevent removal of finished gears and insertion of new blanks during the pas-sage of the blocks along the front of the machine.

Such a machine has been found highly productive and in one illustrative application thereof, finished gears were produced at the rate of siX per minute, which is about as fast as a single operator can remove the finished gears and replace them with new gear blanks.

It will be understood that the gears 61 may be varied in size to correspond to the pitch diameter of the desired gears to be produced, and that the rack plate 69 will be positioned to engage the particular gears 61 in use for a certain operation.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than. as set forth in the claims, but what I claim is:

1. In a machine for broaching gears, a broach-i ing apparatus comprising separate successive broaching sections connected together, means to support said broaching apparatus for feeding movement, gear means directly engaging each broach section so long as it is in the broaching area and positively and continuously advancing said section through said broaching area, means to move a gear blank positively and continuously through said broaching area in engagement with said broaching apparatus and in a plane perpendicular to the plane of operation of said apparatus, and means to positively rotate said gear blank as it is moved through said broaching area.

2. In a broaching machine, a broach formed of a plurality of separate sections connected together and movable in a closed path into, through and out of a broaching area, and a positive gear drive directly engaging and driving each successive section so long as it is in said broaching area.

3. In a broaching machine, a broach formed of a plurality of separate sections connected together and movable in a closed path into, through and out of a broaching area, each broach section having reversed helical rack plates on the back thereof, reversed helical gears located in said broaching area and continuously engaging said rack plates so long as each broach section is in the broaching area, and means to positively rotate said helical gear OLIVER. W. BONNAFE.

REFERENCES CITED The following referenlces are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,469,602 Perkins et al. Oct. 2, 1923 1,712,256 Colman May 7, 1929 2,270,741 Rovick Jan. 20, 1942 2,372,596 Miller Mar.'27, 1945 

